One of the largest issues with the current vaccines is whether they will be effective in individuals most at risk for COVID-19. This is particularly true of the elderly, where immunity tends to be less effective and harder to induce.
Moderna presented evidence today that their vaccine could be effective in elderly individuals older than 71 years.
The titers of antibody (immune proteins) induced in subjects over the age of 71 were similar to those in younger individuals, aged 18-55 or 55 to 70. As shown above, antibodies that neutralize the virus (and protect from infection) were also indistinguishable in younger and older subjects, and were similar to antibody levels in individuals who have recovered from COVID-19 infection.
While the number of subjects is small, this data gives reassurance the vaccine will be useful in protecting the people most at risk from COVID-19. The final proof of this awaits the results of the clinical trials now being conducted.